Peroxisome proliferator-activated receptor γ inhibits pulmonary hypertension targeting store-operated calcium entry

Yingfeng Wang, Wenju Lu, Kai Yang, Yan Wang, Jie Zhang, Jing Jia, Xin Yun, Lichun Tian, Yuqin Chen, Qian Jiang, Bo Zhang, Xiuqing Chen, Jian Wang

In this study, we investigated the role of peroxisome proliferator-activated receptor γ (PPARγ) on store-operated calcium entry (SOCE) and expression of the main store-operated calcium channel (SOCCs) components, canonical transient receptor potential (TRPC) in chronic hypoxia (CH)-induced pulmonary hypertension (CHPH) rat models. Small interfering RNA (siRNA) knockdown and adenoviral overexpression strategies were constructed for loss-of-function and gain-of-function experiments. PPARγ agonist rosiglitazone attenuates the pathogenesis of CHPH and suppresses Hif-1α, TRPC1, TRPC6 expression in the distal pulmonary arteries (PA), and SOCE in freshly isolated rat distal pulmonary arterial smooth muscle cells (PASMCs). By comprehensive use of knockdown and overexpression studies, and bioinformatical analysis of the TRPC gene promoter and luciferase reporter assay, we demonstrated that PPARγ exerts roles of anti-proliferation, anti-migration, and pro-apoptosis in PASMCs, likely by inhibiting the elevated SOCE and TRPC expression. These effects were inhibited under the conditions of hypoxia or Hif-1α accumulation. We also found that under hypoxia, accumulated Hif-1α protein acts as upstream of suppressed PPARγ level; however, targeted PPARγ rescue acts as negative feedback on suppressing Hif-1α level and Hif-1α mediated signaling pathway. PPARγ inhibits CHPH by targeting SOCE and TRPC via inhibiting Hif-1α expression and signaling transduction.